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1896. | NEW YORK ACADEMY OF SCIENCES. 
The pygidium of this species may be distinguished from that 
of A. acutilobus in the fact that the tubercle of the second joint 
encroaches so decidedly on the third joint as to make a strong 
sinus in the dividing furrow; also it may be distinguished by 
the proportionately shorter third joint of the pygidium. This 
species appears to have no lateral spines to the pygidium. 
Agnostus Davints, Hicks. Plate xvi., fig. 6. 
Agnostus Davidis, Hicks. Undescribed fossils of the Mene- 
vian group. Jour. Geol. Soc. London, 1872, p. 173, pl. v., figs. 
2 to 4. 
A large pygidium, about the size of that of Hicks’ species 
above named, occurs at Manuel Brook. It is flattened in the 
shale and so its contour is not known. Dr. Hicks’ examples ap- 
pear to have been distorted by pressure; allowing for this our 
example agrees fairly well with the pygidia he figures ; his de- 
scription of the species is as follows: 
“Head rounded and forming about two-thirds of a circle, and 
about 2 of an inch long, surrounded by a narrow border. The 
glabella occupies about one-third of the width, and tapers for. 
ward. It is divided at the base of the anterior third, by a trans 
verse furrow, into an anterior spheroidal lobe and a posterior- 
elongated lobe, the anterior part of which is raised centrally ; 
there is a triangular lobe on either side at the base of the gla- 
bella. Cheeks slightly raised and gibbous. 
Thorax depressed, strongly trilobed ; pleurze grooved deeply 
to the tips. Axis trilobed, the central lobe being largest and 
pyramidal in shape. The two lateral lobes triangular in shape. 
Tail of the same shape as the head, but more strongly mar- 
gined. The axis is large and occupies more than a third of the 
width, reaches backwards to within a short space of the poste- 
rior margin and is indented by three furrows on each side, each 
running obliquely backwards from the centre, which is somewhat 
raised. 
This is the largest species found in the Menevian group. 
Found at St. David’s and near Dolgelly, North Wales.” 
_ In the American examples I cannot recognize the third fur- 
row of the axis of the pygidium mentioned and figured by Dr. 
Hicks, and on the other hand he does not describe a low tubercle 
which is found on the second lobe of the pygidium in this 
American form. See 
Sculpture. The axis and side lobes are covered with minute 
TRANSACTIONS N. Y. ACAD. Scr., Vol. XV., Sig. 15, September 5, 1896. 
